Floor furnace



Nov. 14, 1950 w. c. COLEMAN FLOOR FURNACE 2 Sheets-Sheet 1 Filed June 16, 1947 Nov. 14, 1950 w. c. COLEMAN FLOOR FURNACE 2 Sheets-Sh'et 2 Filed June 16, 1947 Patented Nov. 14, 1950 2,530,151 FLOOR FURNACE William 0. Coleman, Wichita, Kans., assignor to The Coleman Company, Inc., Wichita, Kans., a corporation of Kansas Application June 16, 1947, Serial No. 755,001

9 Claims.

l This invention relates to furnaces and particularly those of the circulating air type and adapted for underfloor installation.

In furnaces of this character it is desirable to close the burner compartment thereof from the circulating air passageways and supply combustion supportin air from a point exteriorly of the casing. This method of supplying the combustion supporting air eliminates possibility of contamlnation of the circulated ai with gases and products of combustion but when such furnaces are installed in homes having no basements and very little underfloor space, excavations or pits are required to accommodate such heaters. Consequently, these pits being of lower level than the outside ground, may fill with water which results in shutting off the combustion air supply and flooding of the burner so that the flame is extinguished. Thus, such arrangements for admitting combustion supporting air has resulted in other hazards. Another difficulty with such furnaces is the difficulty of making adjustments and repair to the burner.

It is, therefore, an object of the present invention to provide a furnace structure which permits safe supply of external air for combustion purposes and which takes such air from a point above the level to which water may accumulate around the bottom of the furnace casing.

Another object of the invention is to provide a floor furnace which includes an outer casing having a closed bottom and which is provided with a removable false bottom on which the burner, combustion chamber unit and inner casing are all mounted for removal as a single unit through the open top of the outer casin when adjustment and repairs are necessary.

Another object of the invention is to construct the false bottom in association with the closed bottom of the outer casing to provide an adequate air supply duct completely closed off from the air heating ducts or passageways of the furnace.

Further objects of the invention are to provide the furnace with a simple and eflicient means for admitting sufiicient fresh air into one of the air circulating passages of the furnace for maintaining wholesome atmospheric conditions in the space heated, and to provide for control of the fresh air supply readily accessible from above the floor in which the furnace is installed.

In accomplishing these and other objects of the invention, I have provided improved structure, the preferred form of which is illustrated in the accompanying drawing wherein:

Fig. l is an underneath perspective view of a floor furnace embodying the features of the present invention, a portion of the outer casing being broken away to better illustrate the interior construction.

Fig. 2 is a vertical cross section through the furnace when installed in a floor opening, the section being taken through the furnace casing on the line 22 of Fig. 4.

Fig. 3 is a detail section through one of the flue connections on the line 3-3 of Fig. 2.

Fig. 4 is a longitudinal vertical section through the furnace on the line 4-4 of Fig. 2.

Fig. 5 is a cross section through the bottom portion of a floor furnace showing a modified form of the invention.

Referring more in detail to the drawings:

I designates a furnace constructed in accordance with the present invention and which includes an outer casing 2 having side walls 3-4, end walls 5-6, a bottom I of novel construction and an open top 8 that is covered by a floor grill 9. The side and end walls are joined together and with the bottom by leak-tight joints to prevent infiltration of water and other elements should the furnace be installed in locations where flooding is likely to occur.

The bottom 1 is of pan-like formation and includes a substantially flat portion l0 extending longitudinally midway between the side walls 3 and 4. The bottom further includes side portions l I and I2 diverging upwardly and outwardly from the longitudinal sides of the portion 10 and which join with the side walls 3 and 4. The pan-like bottom has closed ends l5 and I6 preferably located in the plane of the end walls 5 and 6.

Removably supported within the outer casing on the bottom thereof is a false bottom l3 carrying a heating unit I! and an inner casing 18. The false bottom includes a substantially flat horizontal portion l9 having sufficient width to seat the combustion chamber of the heating unit and having a length to extend from the end wall 5 to the end wall 6. The false bottom also includes side portions 20 and 2| that curve downwardly and outwardly from the sides of the horizontal portion l9 and terminate in reversely curving seating flanges 22 and 23 that seat upon the upwardly sloping portions II and 12 at the sides of the pan bottom 1 as best shown in Fig. 2. The central portion of the false bottom is thus spaced above the bottom of the casing to provide an air space 24 extending centrally along the length of the casing for the purpose later to be described.

The inner casing l8 has side walls 25 and 26 spaced from the corresponding side walls 3 and 4 of the outer casing and end walls 21 spaced from the corresponding end walls and 6 to provide downflow passageways 28 therebetween. The lower edges 24 of the side and end walls of the inner casing terminate above the bottom 1 to provide outlets 29 for the downflow passageways and to connect with upflow passageways 30 at the sides of the heating unit IT. The upper portions of the end and side walls of the inner casing are drawn inwardly as indicated at 3| to provide enlarged entrances to the passageways 28 for facilitating entrance of air to be heated at the margins of the grill 9 and to provide a somewhat restricted outlet 32 for the air after it has been heated by the heating unit IT. The end walls of the inner casing are supported directly upon the horizontal portion of the false bottom and are attached thereto by brackets 33.

In the illustrated instance the heating unit includes a central combustion chamber section 34 (previously mentioned) having side walls 35 and 36 supported on the substantially horizontally disposed portion [9. The side walls 35 and 36 extend parallel with the side walls of the inner and outer casing and are connected at the ends and top by curvatures 31 in forming a combustion chamber completely isolated from the down and updraft passageways. The upper portion of the combustion chamber section has lateral outlets 38 and 39 for discharge of the hot products of combustion through radiator sections 40 and 4!, before discharge through the flue connections 42 which are connected with pipes 43 extending through the end walls of the outer casing. The flue connections 42 are removably coupled with the pipes 43 by bands 44 that are contracted therearound to provide leak-tight joints. The flue pipes 43 are preferably interconnected exteriorly of the furnace by means of a chimney downdraft diverter 45.

In order to insulate the heating effects of the heating unit I! from the walls of the inner casing, the inner casing is provided with a liner 46 having walls spaced from corresponding walls of the inner casing to provide secondary upflow passageways 41 for a portion of the air discharged from the lower ends of the downflow passageways 28.

The heating unit is equipped with a burner 48 that extends longitudinally within the air chamher or space 24 and has a series of fuel discharge jets 49. The burner 48 is suspended below the horizontal portion of the false bottom by brackets 50 and the jets 49 project through openings 5| in the false bottom into the combustion chamber as best shown in Figs. 2 and3. The jets receive their primary combustion air below the false bottom and the openings 5| are of slightly larger size to pass secondary combustion supporting air in close contact with the flames.

Combustion supporting air is supplied to the space 24 from a point exteriorly of the furnace entirely independent of the air circulated through the passageways by providing the end of the pan-like bottom 1 with an air inlet conduit 52. The conduit 52 includes an elbow 54 attached to the end of the pan-like bottom by a flange 53 that encircles an opening 53 therein. The

elbow 54 is turned upwardly and supports a pipelike duct 55. The upper end of the duct 55 terminates at a point above the level of any water that is likely to leak into the excavation or pit 56 in which the furnace depends. It is thus obvious that the air supporting combustion is taken from above the level of such water and that the duct and its connection with the furnace structure excludes entrance of any water that would ordinarily cause flooding of the burner through the air inlet. The central portion of the false bottom l3 extends above the air outlet of the air supply conduit 52 and has an end portion I3 in sliding contact with the side wall to which the conduit is connected, when the false bottom and heating unit are inserted and removed from the casing.

The burner is supplied with fuel through a pipe 51 that extends upwardly within one of the downdraft passageways to a point accessible through the open top of the casing where it terminates in an L fitting that is connected by means of a union 58 with a supply pipe extending through the side wall of the outer casing.

The structure thus far described provides an adequate supply of exterior combustion supporting air for the burner. However, when such a furnace is installed in a home built in accordance with the present high standards of construction very little fresh air filters into the space being heated and to maintain wholesome atmospheric conditions, I have provided the outer casing of the furnace with means for admitting a controlled amount of fresh air for mixture with the air circulated through the furnace. This is effected by providing at least one of the walls of the outer casing of the furnace, preferably one of the side walls, with an elongated substantially horizontally arranged air inlet opening 59 that is located at a level above which any water may accumulate around the furnace casing.

In order to control the amount of air admitted and to guide the air moving downwardly through the downflow passageway across the air inlet opening 59 I provide a door or damper 60 that is preferably larger than the opening so that the marginal edges may lap thereover when the door is closed. The upper edge of the door is pivotally connected with the inner face of the side wall along the upper edge of the opening by suitable hinges 6| so that the door may be swung inwardly to admit the amount of fresh air desired. The position of the door is regulated by means of a screw 62 that is adjustably threaded through an opening 63 in the lower edge of the door and which is adapted to bear against the side wall of the outer casing as best shown in Fig. 2. The screw has a weighted head 64 on the inner end thereof so as to resist inward swinging movement of the door. The weighted head of the screw is readily accessible from above the floor 66 in which the furnace is installed upon removal of the grill 9. By turning the screw in the desired direction the door is adjusted so that it stands open a distance sufiicient for admitting the desired amount of fresh air.

The furnace constructed and assembled as described may be suspended within an opening 68 provided in the floor 66. If there is not sufficient space below the floor to accommodate the furnace, a pit 56 is provided to accommodate the lower portion thereof without the hazard of flooding of the burner since the bottom is completely enclosed and a duct may be provided so that the inlet end thereof is above the level of any water that may accumulate in the pit. Tight connections are made with the flue and the burner is connected to a suitable source of fuel supply.

When the furnace is placed in operation by turning on the fuel and lighting the burner, combustion supporting air is admitted through the inlet end of the duct 55 by reason of the draft through the flue connection so that the combustion supporting air is drawn into the air chamber or space 24 to supply the burner with primary and secondary air entirely independent of air flow to and from the space being heated. As the furnace heats the cold air surrounding the heating unit I! warms and is displaced upwardly through the floor grill 9 into the space being heated by the cold air moving downwardly in the downfiow passageways 28 and upwardly through the air flow passageways 30 surrounding the heating unit with the result that a constant circulation is maintained through the furnace. If sufficient fresh air is not being supplied to the space being heated, the grill 9 may be removed to permit access to the adjusting screw 62 of the door 60. The screw 62 may be rotated so as to raise the door 60 from the opening 59 a distance sufficient for admitting the proper amount of fresh air necessary to maintain a wholesome condition in the space being heated.

Should it become necessary to service and repair the heating unit, the floor grill 9 is removed and the entire heating unit assembly I! including the false bottom is readily removed through the open top 8 of the furnace casing 2 so that the work may be completed above the floor 65,

after which the entire assembly may be replaced through the open top 8 of the outer casing and lowered into position until the curved flanges 22 and 23 of the false bottom again seat upon the portions H and [2 of the furnace bottom 1.

Fig. shows a modified form of furnace bot tom 69 having downwardly and inwardly rounding sides 10 merging into a substantially flat horizontal portion H extending longitudinally below the combustion chamber but which may be slightly dropped as indicated at 12 for seating the false bottom 13 which in this case is relatively narrow and has downwardly diverging sides 14 and I5 straddling the raised portion of the bottom and cooperating therewith to provide the close air passageway l6 in which the burner 11 is suspended. The construction of the other portions of the furnace may be identical with those illustrated and described in connection with the preferred form of the invention previously described.

From the foregoing it is obvious that I have provided an underfloor furnace which avoids flooding hazards and which also admits sufficient exterior fresh air from an underfloor space through separate inlets for supplying combustion supporting air to the burner and a sufiicient amount of fresh air to maintain wholesome conditions in the space heated.

What I claim and desire to secure by Letters Patent is:

1. In a furance of the character described, an open top outer casing having a closed bottom, a heating unit in the outer casing having a combustion chamber, an inner casing having walls spaced from walls of the outer casing to provide downflow air passageways and surrounding the heating unit to provide upflow passageways around said heating unit in connection with the downflow passageways, a false bottom member cooperating with the bottom of the casing for providing an air supply chamber and having means for supplying combustion supporting air to the combustion chamber of the heating unit and having sides engaging said outer casing bottom below the air passageways for forming the bottom of said passageways and to direct air from the downflow air passageways to the upfiow air passageways, and a duct having an inlet located exteriorly of said outer casing at a point sub stantially above said bottom and having outlet into said air supply chamber for conducting combuston supporting air into the air supply chamher.

2. In a furnace of the character described, an open top outer casing, a bottom for the casing having a low central portion and upwardly and outwardly diverging portions joining with side walls of said casing, a removable false bottom member extending across said casing in spaced relation with said low portion and having sides seating on the diverging portions to maintain said spaced relation and cooperate with said casing bottom in forming a supply chamber for combustion supporting air, and a heating unit in the casing above said false bottom member and having a combustion chamber in communicating relation with said air supply chamber.

3. In a furnace of the character described, an open top outer casing, a bottom for the casing having a low central portion and upwardly and outwardly diverging portions joining with side walls of said casing, a removable false bottom member extending across said casing in spaced relation with said low portion and having sides seating on the diverging portions to maintain said spaced relation and cooperate with said casing bottom in forming a supply chamber for combustion supporting air, a heating unit supported in the casing by said false bottom member and including a burner in communicating relation with said air supply chamber, and means for supplying combustion supporting air from a point exteriorly of the casing to said supply chamber for use in supporting combustion of fuel supplied to said burner.

4. In a furnace of the character described, an open top outer casing, a bottom for the casing having a low central portion and upwardly and outwardly diverging portions joining with side walls of said casing, a false bottom member extending across said casing in spaced relation with said low portion and having sides seating on said diverging portions of said bottom to form a supply chamber for combustion supporting air, a heating unit supported in the casing by said false bottom member and including a burner in communicating relation with said air supply chamber, and a duct exteriorly of the outer casing and having an inlet end located at a relatively high point above the casing bottom and connected with the supply chamber for furnishing combustion supporting air to said burner.

5. In a furnace of the character described, an open top outer casing, a bottom for the casing having a low central portion and upwardly and outwardly diverging portions joining with side walls of said casing, a false bottom member extending across said casing in spaced relation with said low portion and having air directing sides seating on said diverging portions to support said false bottom to form a supply chamber for combustion supporting air, a heating unit supported in the casing by the false bottom member and including a burner in communicating relation with said air supply chamber, means for supplying combustion supportingair from a point exteriorly of the casing to said supply chamber for use in supporting combustion of fuel supplied to said burner, and an inner casing surrounding the heating unit and having walls spaced from walls of said outer casing and from said heating unit to provide down and updraft passageways over said air flow directing sides of the false bottom, said passageways being separated from the combustion air supply chamber by said false bottom member.

6. In a furnace of the character described, an open top outer casing, a bottom for the casing having a low centralportion and upwardly and outwardly diverging portions joining with side walls of said casing, a false bottom member extending across said casing in spaced relation with said low portion and having sides seating on upper diverging portions to form a supply chamber for combustion supporting air, a heating unit supported in the casing by said false bottom member and including a burner in communicating relation with said air supply chamber, means for supplying combustion supporting air from a point exteriorly of the casing to said supply chamber for use in supporting combustion of fuel supplied to said burner, and an inner casing surrounding the heating unit and having walls spaced from walls of said outer casing and from said heating unit to provide down and updraft passageways, said false bottom member having curved side portions under walls of the inner casing to guide circulated air from the downfiow passageways to the upflow passageways.

7. In a furnace of the character described, an open top outer casing having a closed bottom, a removable heating unit in the outer casing, and having a burner, an inner casing having walls spaced from walls of the outer casing to provide downfiow air passageways and surrounding the heating unit to provide upfiow passageways around said heating unit in connection with the downflow passageways, means forming an attached part of the heating unit and cooperating with the bottom of the casing for providing an air supply chamber closed from the air passageways, said means having communicating relation with the burner for supplying combustion supporting air, a duct located exteriorly of the outer casing and having an inlet at a point substantially above said bottom, and having connection with the air supply chamber for conducting combustion supporting air into the air supply chamber, said means having air directing portions extending under the upfiow passageways on respective sides of the air duct connection for directing downflow air upwardly of the upflow passageways.

8. In a furnace of ,the character described, an open top outer casing having'a closed bottom, an air supply duct having an outlet connected with a side wall of the casing near said closed bottom and extending upwardly along the exterior side of the casing to provide an air inlet located a substantial distance above said closed bottom, a removable bottom cooperating with said casing to provide a combustion air supply chamber in communicating relation with said outlet of the air supply duct and having a portion extending above said outlet connection and having an edge portion in sliding contact with said side wall of said casing upon removal or insertion of said bottom, and a heating unit in the outer casing supported by said removable bottom and having a burner in communicating relation with the air supply chamber.

9. In a furnace of the character described, an open top outer casing having a closed bottom, an air supply duct having an outlet connected with a side wall of the casing near said closed bottom and extending upwardly along the exterior side of the casing to provide an air inlet located a substantial distance above said closed bottom, a removable bottom cooperating with'said casing to provide a combustion air supply chamber in communicating relation with said outlet of the air supply duct and having a portion extending above said outlet connection and having an edge portion in sliding contact with the wall of said casing upon removal and insertion of said bottom, a heating unit in the outer casing supported by said removable bottom and having a burner in communicating relation with the air supply chamber, and means connecting the removable bottom with said heating unit for removal of said bottom along with said heating unit.

WILLIAM C. COLEMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 244,785 Baker July 26, 1881 739,780 Ernst Sept. 22, 1903 887,915 Burk May 19, 1908 1,766,394 Miller et al. June 24, 1930 2,086,301 Olds July 6, 1937 2,162,410 Stephens -June 13, 1939 2,200,645 Stephens May 14, 1940 2,324,862 Martin July 20, 1943 

